Slight Mouth Breathing

[Mistyridgechickens]

Hey all, I have a hen who’s about 3 years old who I’ve noticed is doing a bit of mouth breathing and you can see that she’s breathing harder when she’s roosting. It is very slight, and I’m not hearing any rasping or gurgling type noises, but it has been going on for two days now. Is it likely a respiratory infection? And if so, is there an OTC medicine I can give her, or do I need to find a vet? I live in the USA. Thanks in advance, she’s very precious to me so I’m very worried about her

 

[Wyorp Rock]

Can you get a video of her?

Upload video to youtube and provide a link.

She's 3 years old, does she lay eggs? When was her last one?
Any bloat, fluid or heaviness in the abdomen below the vent between the legs?
Is her crop emptying?
Any signs of respiratory illness like mucous, facial swelling, bubbles in the eyes, coughing, sneezing?
Have you added any new birds recently?

More noticeable when roosting - is there adequate ventilation in the coop? She may be roosting in a position that's placing more pressure on her abdomen and air sacs resulting in a bit of labored breathing.

 

[Mistyridgechickens]

Can you get a video of her?

Upload video to youtube and provide a link.

She's 3 years old, does she lay eggs? When was her last one?
Any bloat, fluid or heaviness in the abdomen below the vent between the legs?
Is her crop emptying?
Any signs of respiratory illness like mucous, facial swelling, bubbles in the eyes, coughing, sneezing?
Have you added any new birds recently?

More noticeable when roosting - is there adequate ventilation in the coop? She may be roosting in a position that's placing more pressure on her abdomen and air sacs resulting in a bit of labored breathing.

No new birds recently. Crop is emptying. No other respiratory illness signs. There might be some bloating in her abdomen; it’s like moderately squishy and feels kinda full, but it’s not like one pouch that’s standing out. She does lay eggs but she’s never been the biggest layer, maybe 2-3 a week; her last one was Thursday.
She does tend to sit on a wider roost, probably about 6 inches, so that could be part of it.
I’m unsure about our ventilation. Our chicken coops are outward facing horse stalls in our barn; they have a 3x3ft window in the doors, and there’s a gap at the top of the wall in between the two stalls of 2-3 feet, and then another gap of about a foot on the opposite side of the stall this hen is in that leads to a small feed room that we keep the door open to during the day but close at night in case of predators. Sorry for the long explanation, I wasn’t able to get a picture today.
Here’s a video from this afternoon:

 

[Wyorp Rock]

I'd look inside her beak for any mucous, canker/yellow or white pasty material.

The shaking of the head, do look inside her ears for infection or pus too.

Check her over for lice/mites.

Hard to know if she's having respiratory symptoms or something else is going on. If it worsens, then seeking vet care is always best. If that's not possible, then treating with an antibiotic like Tylan/Tylosin can be tried to see if that helps.